TRAVELING WAVE TUBE AND HIGH-FREQUENCY CIRCUIT SYSTEM

Description

[Technical Field]

[0001] The present invention relates to a high-frequency circuit system comprising a traveling wave tube and equipped with a power supply device to supply the required direct-current high voltage to each electrode of the traveling wave tube.

[Background Art]

[0002] The traveling wave tube is an electron tube used for the amplification of an RF (Radio Frequency) signal, the oscillation, or the like by the interaction between an electron beam emitted from an electron gun and a high-frequency circuit. For example, as shown in Fig. 6, a traveling wave tube 1 includes an electron gun 10, a helix 20, a collector 30, and an anode 40. The electron gun 10 emits electrons. The helix 20 is a high-frequency circuit in which an electron beam 50 formed of electrons emitted from the electron gun 10 interacts with the RF signal. The collector 30 captures the electron beam 50 outputted from the helix 20. The anode 40 leads out electrons from the electron gun 10 and guides the electrons emitted from the electron gun 10 inside the helix 20 that is spiral-shaped.

[0003] The electron gun 10 includes a cathode 11 which emits electrons (thermal electrons), a heater 12 which gives heat energy for emitting the electrons (thermal electrons) to the cathode 11, and a wehnelt 13 which forms the electron beam 50 by focusing the electrons emitted from the cathode 11. For example, the cathode 11 is made with a disc-shaped cathode pellet consisting of a porous tungsten base which is impregnated with an oxide (an emitter material) such as barium (Ba) or the like. For example, an electron gun (a pierced electron gun) equipped with the wehnelt 13 is described in patent literature 1 (PTL1) and the like.

[0004] The electrons emitted from the electron gun 10 are accelerated by the electric potential difference between the cathode 11 and the anode 40 while forming the electron beam 50 and guide into the helical structure of the helix 20. The electrons guided into the helical structure of the helix 20 travel through the helical structure of the helix 20 while the introduced electrons interact with an RF signal inputted from one end of the helix 20. The electron beam 50 which passes out through the helical structure of the helix 20 is captured by the collector 30. At this time, the RF signal amplified by the interaction with the electron beam 50 is outputted from the other end of the helix 20.

[0005] In the electron beam 50, because the electrons with a negative charge are repelled from each other by the coulomb force, diameter of the electron beam 50 is increased according to the travel distance of the electron. Accordingly, a periodic magnetic field generation device (not shown) which generates the magnetic field for suppressing the expansion of the electron beam 50 passing through the helical structure of the helix 20 is disposed in the periphery of the helix 20 and the diameter of the electron beam 50 is kept constant over the whole length of the helix 20 by the magnetic field generated by the periodic magnetic field generation device. The periodic magnetic field generation device is described in, for example, patent literature 2 (PTL2).

[0006] Further, in patent literatures 3 and 4 (PTL3 and PTL4), it is described that the electron beam can be controlled by the magnetic field. In PTL3, it is described that magnetic field applying means such as a coil or the like is used for deflecting the electron beam. Further, in PTL4, it is described a structure in which in order to prevent the electron gun from being magnetized and thereby keep the trajectory of the electron beam stable, magnetic erasing means composed of a coil is disposed in the periphery of the electron gun.

[0007] As shown in Fig. 6, a negative direct-current high voltage (body voltage Ebody) determined by using an electric potential HELIX of the helix 20 as a reference is supplied to both the cathode 11 and the wehnelt 13 from a power supply device (not shown). A positive or negative direct-current voltage (in Fig. 6, a negative voltage: a heater voltage Ef) determined by using an electric potential H/K of the cathode 11 as a reference is supplied to the heater 12. A positive direct-current high voltage (an anode voltage Ea) determined by using the electric potential H/K of the cathode 11 as a reference is supplied to the anode 40. Further, a positive direct-current high voltage (a collector voltage Ecol) determined by using the electric potential H/K of the cathode 11 as a reference is supplied to the collector 30. Usually, the helix 20 is connected to a case (a body) of the traveling wave tube 1 and grounded.

[0008] Fig. 6 shows an example of a structure of the traveling wave tube 1 including one collector 30. However, the traveling wave tube 1 may have a structure in which a plurality of the collectors 30 are included. Further, Fig. 6 shows an example in which the anode voltage Ea is supplied to the anode 40. However, the traveling wave tube 1 may be used in a state in which the anode 40 is grounded. Further, Fig. 6 shows an example in which the wehnelt 13 is connected to the cathode 11. However, the traveling wave tube 1 may have a structure in which a positive or negative direct-current voltage (a wehnelt voltage Ew) determined by using the electric potential of the cathode 11 as a reference is supplied to the wehnelt 13.

[0009] In the traveling wave tube 1 shown in Fig. 6, an amount of the electrons emitted from the cathode 11 can be controlled by the anode voltage Ea and the electric power of the RF signal outputted from the traveling wave tube 1 can be controlled by the anode voltage Ea. The similar control can be performed by the wehnelt voltage Ew applied to the wehnelt 13. Further, an amount of the electrons which can be emitted from the cathode 11 depends on the temperature of the cathode 11, in other words, the temperature of the heater 12. Therefore, in the traveling wave tube 1, the heater voltage Ef is set according to the output power of the RF signal.

[0010] For example, in patent literature 5 (PTL5), it is described a structure in which the electric power of the RF signal outputted from the traveling wave tube 1 is controlled by the anode voltage Ea. In PTL5, it is described that the output power of the RF signal is controlled by the anode voltage Ea and the heater voltage Ef is adjusted according to the output power of the RF signal.

[Citation List]

[Patent Literature]

[0011] 

[PTL1] Japanese Patent Application Laid-Open No. 2006-127899

[PTL2] Japanese Patent Application Laid-Open No. Hei 09-274865

[PTL3] Japanese Patent Application Laid-Open No. 2002-198002

[PTL4] Japanese Patent Application Laid-Open No. 2007-273158

[PTL5] Japanese Patent Application Laid-Open No. Sho 58-157206 US 2 945 153 A refers to electron beam tubes and in particular to focussing means for such tubes. US 2 841 739 A refers to systems for focussing a stream of charged particles, and particularly for keeping electron beams cylindrical over a long path.

[Summary of Invention]

[0012] A case in which the electric power of the RF signal outputted from the traveling wave tube 1 is controlled by the anode voltage Ea or the wehnelt voltage Ew will be described. Namely, when the traveling wave tube 1 is operated in a multi-mode in which the traveling wave tube 1 operates at two or more RF output power levels, usually, a heater temperature is set to a temperature corresponding to a high power mode in which the output power of the RF signal is maximum.

[0013] This is because when the heater temperature is set to a temperature corresponding to a low power mode in which the output power of the RF signal is low, the amount of electrons emitted from the cathode 11 is insufficient at the time of the high power mode and whereby, the output power of the RF signal is saturated at an output power level lower than the required maximum output power.

[0014] However, when the cathode temperature is increased by raising the temperature of the heater, an amount of evaporation of the emitter material with which the above-mentioned cathode pellet is impregnated increases. Therefore, a time taken to deplete the entire emitter material is shortened. Further, when the cathode pellet is impregnated with barium (Ba) as the emitter material, not only barium (Ba) evaporates as an oxide but also barium (Ba) itself that is a metal evaporates. Therefore, when the cathode temperature is increased by raising the temperature of the heater, a withstanding voltage characteristic of the traveling wave tube 1 rapidly deteriorates. Accordingly, even when the traveling wave tube 1 is operated in the low power mode for a long time, the product life thereof is shortened by about the product life of the traveling wave tube 1 operated in the high power mode at all times.

[0015] Accordingly, when the traveling wave tube 1 is operated in the multi-mode, as described in PTL5, when the traveling wave tube 1 is operated in the high power mode, the temperature of the heater is raised and when the traveling wave tube 1 is operated in the low power mode, the temperature of the heater is lowered. Thus, when the heater temperature is changed according to the operation mode, it is expected that the product life of the traveling wave tube 1 can be extended. However, when the structure in which the heater temperature is changed according to the operation mode is used, another problem described below occurs.

[0016] For example, when the traveling wave tube 1 is designed so that the optimal trajectory of the electron beam 50 can be obtained when the traveling wave tube operates in the high power mode, the amount of electrons emitted from the cathode 11 when the traveling wave tube operates in the low power mode is smaller than the amount of electrons emitted from the cathode 11 when the traveling wave tube operates in the high power mode and the diameter of the electron beam 50 becomes small at the time of the low power mode. For this reason, the interaction between the electron beam 50 and the RF signal inputted to the helix 20 becomes weak and whereby, the gain of the traveling wave tube 1 operating in the low power mode becomes smaller than the gain of the traveling wave tube 1 operating in the high power mode. Thus, when the structure in which the gain changes according to the operation mode is used but the output power of the RF signal has to be kept constant even when changing the operation mode, it is necessary to change the electric power of the RF signal inputted to the traveling wave tube 1 according to the operation mode. Therefore, the convenience of the traveling wave tube 1 decreases.

[0017] Further, when the traveling wave tube 1 is designed so that the optimal trajectory of the electron beam 50 can be obtained when the traveling wave tube operates in the high power mode, a problem in which an amplification efficiency of the traveling wave tube 1 operating in the low power mode decreases also occurs.

[0018] It is known that in the periodic magnetic field generation device mentioned above, when the diameter of the electron beam 50 is small, it is necessary to increase the peak value of a magnetic flux density (refer to PTL2). For this reason, the periodic magnetic field generation device is designed so that the optimal peak value of the magnetic flux density can be obtained according to the diameter of the electron beam 50.

[0019] Therefore, when the traveling wave tube operates in the low power mode, the amount of electrons emitted from the cathode 11 is decreased and the diameter of the electron beam 50 is decreased. Whereby, the magnetic flux density obtained by the periodic magnetic field generation device is relatively decreased and a force for focusing the electron beam 50 is decreased. As a result, as shown in Fig. 7, a ripple of which the diameter of the electron beam 50 periodically changes is generated, the interaction between the electron beam 50 and the RF signal becomes weak, and whereby, the amplification efficiency of the traveling wave tube 1 decreases.

[0020] On the other hand, when the traveling wave tube 1 is designed so that the optimal trajectory of the electron beam 50 can be obtained when the traveling wave tube operates in the low power mode, the amount of electrons emitted from the cathode 11 when the traveling wave tube operates in the high power mode is greater than the amount of electrons emitted from the cathode 11 when the traveling wave tube operates in the low power mode and the diameter of the electron beam 50 becomes large at the time of the high power mode. Therefore, the interaction between the electron beam and the RF signal inputted to the helix 20 becomes strong, the gain of the traveling wave tube 1 operating in the high power mode is greater than the gain of the traveling wave tube 1 operating in the low power mode, and the RF signal can be easily oscillated. Further, when the diameter of the electron beam 50 is increased, the collision between the electron and the helix 20 easily occurs and whereby, the current (helix current) flowing through the helix 20 increases and the power consumption of the traveling wave tube 1 increases.

[0021] The present invention is made to solve the above-mentioned problem. The object of the present invention is to provide a traveling wave tube which is operated in the multi-mode, can extend the product life, and can suppress a gain change and an amplification efficiency change that occur when the operation mode is changed and a high-frequency circuit system.

[Solution to Problem]

[0022] The invention is defined by the independent claims. Dependent claims refer to preferred embodiments.

[0023] To achieve the above-mentioned object, a high-frequency circuit system comprises the combination of features according to claim 1.

[Advantageous Effect of Invention]

[0024] According to the present invention, in a traveling wave tube operated in the multi-mode, the product life can be extended and a gain change and an amplification efficiency change that occur when the operation mode is changed can be suppressed.

[Brief Description of Drawings]

[0025] 

[Fig. 1] Fig. 1 is a schematic diagram showing an example of a structure of a high-frequency circuit system according to an example embodiment of the present invention.

[Fig. 2] Fig. 2 is a circuit diagram showing an example of a configuration of a power supply device included in a high-frequency circuit system according to an example embodiment of the present invention.

[Fig. 3] Fig. 3 is a schematic diagram showing an example of another structure of a high-frequency circuit system according to an example embodiment of the present invention.

[Fig. 4] Fig. 4(a) is a schematic diagram showing a state of a magnetic field generated by a magnetic field application device and a periodic magnetic field generation device and Fig. 4(b) is an enlarged schematic diagram showing a main part of Fig. 4(a).

[Fig. 5] Fig. 5(a) is a schematic diagram showing operation at a time of a high power mode of a modification example of a high-frequency circuit system according to an example embodiment of the present invention, and Fig. 5(b) is a schematic diagram showing operation at a time of a low power mode of a modification example of a high-frequency circuit system according to an example embodiment of the present invention.

[Fig. 6] Fig. 6 is a schematic diagram showing an example of a structure of a high-frequency circuit system according to the background art.

[Fig. 7] Fig. 7 is a schematic diagram showing a ripple on an electron beam that is generated at a time of a low power mode.

[Description of Embodiments]

[0026] Next, the present invention will be described by using drawings.

[0027] Fig. 1 is a schematic diagram showing an example of a structure of a high-frequency circuit system according to the present invention. Fig. 2 is a circuit diagram showing an example of a configuration of a power supply device included in a high-frequency circuit system according to the present invention. Fig. 3 is a schematic diagram showing an example of another structure of a high-frequency circuit system according to the present invention.

[0028] As shown in Fig. 1, the high-frequency circuit system according to the present invention includes a traveling wave tube 2, and a power supply device 60 which supplies a required direct-current high voltage (a power supply voltage) to each electrode of the traveling wave tube 2.

[0029] The traveling wave tube 2 according to the present invention has a structure in which a magnetic field application device 70 which generates the magnetic field for controlling diameter of an electron beam 50 and to which an electric power for generating the magnetic field is supplied from the outside is added to the traveling wave tube 1 according to the background art shown in Fig. 6. The structure other than the above-mentioned structure is the same as that of the traveling wave tube 1 according to the background art shown in Fig. 6. Therefore, the description for the structure other than the above-mentioned structure will be omitted.

[0030] The magnetic field application device 70 may be realized by forming a coil between a rear side of an electron gun 10 facing an electron emitting surface and a seal plate 21 for vacuum sealing of a chassis (body) of the traveling wave tube 2. In this case, it is desirable to use the seal plate 21 made of a magnetic metal material (magnetic substance material). By using the seal plate 21 made of the magnetic metal material (magnetic substance material), the magnetic field generated when a current flows through the coil can be strengthened. The coil of the magnetic field application device 70 is formed so that the magnetic field including a magnetic line of force whose direction is approximately orthogonal to the electron emitting surface of a cathode 11 is generated when the current flows through the coil.

[0031] Further, the magnetic field application device 70 does not necessarily have a structure in which the coil is made by directly winding a wire around the seal plate 21. The magnetic field application device 70 can have an arbitrary structure in which the coil can generate the magnetic field including the magnetic line of force that is approximately orthogonal to the electron emitting surface of the cathode 11. For example, the magnetic field application device 70 may have a structure in which a ring-shaped magnetic substance core made of a magnetic metal material (magnetic substance material) is disposed in the periphery of the seal plate 21 and the coil is formed on the periphery of the magnetic substance core.

[0032] The electric power is supplied to the coil of the magnetic field application device 70 from a magnetic field application power supply 65 described later included in a power supply device 60. In other words, a coil voltage is supplied to the coil of the magnetic field application device 70 from the magnetic field application power supply 65 mentioned later. A heater power supply 63 described later of the power supply device 60 supplies the heater voltage Ef to a heater 12 of the electron gun 10. The magnetic field application power supply 65 may be composed of a dedicated power supply circuit. As described later, the magnetic field application power supply 65 may be integrated with the heater power supply 63 which supplies the electric power to the heater 12. Fig. 1 shows an example of a structure in which the magnetic field application power supply described later is integrated with the heater power supply and the heater power supply supplies the heater voltage Ef to both the magnetic field application device 70 and the heater 12. In Fig. 1, one end of the heater 12 of the electron gun 10 is connected to one end of the coil of the magnetic field application device 70. Fig. 1 shows an example of a structure in which the heater voltage Ef is supplied to the one end of which the one end of the heater 12 and the one end of the coil of the magnetic field application device 70 are connected to each other.

[0033] As shown in Fig. 2, the power supply device 60 includes a helix power supply 61, a collector power supply 62, the heater power supply 63, an anode power supply 64, and the magnetic field application power supply 65. The helix power supply 61 of the power supply device 60 supplies the body voltage Ebody that is a negative direct-current voltage determined by using the electric potential HELIX of a helix 20 as a reference to the cathode 11. The collector power supply 62 of the power supply device 60 supplies the collector voltage Ecol that is a positive direct-current voltage determined by using the electric potential H/K of the cathode 11 as a reference to the collector 30. The heater power supply 63 of the power supply device 60 supplies the heater voltage Ef that is a positive or negative direct-current voltage (in Fig. 2, a negative direct-current voltage) determined by using the electric potential H/K of the cathode 11 as a reference to the heater 12. The anode power supply 64 of the power supply device 60 supplies a positive direct-current voltage (anode voltage Ea) determined by using the electric potential H/K of the cathode 11 as a reference to an anode 40. The magnetic field application power supply 65 of the power supply device 60 supplies a coil voltage Es that is a positive or negative direct-current voltage (in Fig. 2, a negative direct-current voltage) determined by using the electric potential H/K of the cathode 11 as a reference to the magnetic field application device 70. For example, the helix 20 is connected to the case (body) of the traveling wave tube 2 and grounded inside the power supply device 60.

[0034] In the high-frequency circuit system shown in Fig. 3, the heater 12 receives the heater voltage Ef supplied from the heater power supply 63 of the power supply device 60 shown in Fig. 2 and the coil of the magnetic field application device 70 receives the coil voltage Es supplied from the magnetic field application power supply 65 of the power supply device 60 shown in Fig. 2. In the high-frequency circuit system shown in Fig. 3, the magnetic field application power supply 65 which supplies the coil voltage Es is disposed separately from the heater power supply 63 which supplies the electric power to the heater 12.

[0035] Each of the heater power supply 63, the anode power supply 64, and the magnetic field application power supply 65 included in the power supply device 60 has a structure in which the output voltage can be changed according to the operation mode of the traveling wave tube 2.

[0036] For example, the heater power supply 63 has a structure in which a plurality of power supply circuits, each of which generates the heater voltage Ef for each operation mode, are included and the heater voltage Ef supplied to the heater 12 is changed by a switch according to the operation mode of the traveling wave tube 2. Fig. 2 shows an example of a structure in which two power supply circuits connected in series are included and the electric power is supplied to the heater 12 from one of two power supply circuits or two power supply circuits according to the operation mode. As the power supply circuit for generating the heater voltage Ef, for example, a well-known DC-DC converter including an inverter, a transformer, a rectifier circuit, a capacitor for rectification, and the like may be used.

[0037] For example, the anode power supply 64 has a structure in which a plurality of power supply circuits, each of which generates the anode voltage Ea for each operation mode, are included and the anode voltage Ea supplied to the anode 40 is changed by a switch according to the operation mode of the traveling wave tube 2. Fig. 2 shows an example of a structure in which two power supply circuits connected in series are included and the electric power is supplied to the anode 40 from one of two power supply circuits or two power supply circuits according to the operation mode. As the power supply circuit for generating the anode voltage Ea, the well-known DC-DC converter may be used like as the heater power supply 63.

[0038] When the traveling wave tube 2 is operated in the high power mode, a positive direct-current high voltage (a first anode voltage) that has a large difference from the cathode potential H/K is supplied to the anode 40. The anode power supply 64 may have a structure in which it is connected to the ground potential by using a switch at the time of the high power mode.

[0039] On the other hand, when the traveling wave tube 2 is operated in the low power mode, a positive direct-current high voltage (a second anode voltage) that has a small difference from the cathode potential H/K and is smaller than the voltage supplied when the traveling wave tube 2 is operated in the high power mode is supplied to the anode 40.

[0040] Further, usually, only a small electric current flows into the anode 40. Accordingly, the anode power supply 64 having a large electric current supply capacity is not required. Therefore, for example, the anode power supply 64 may be realized by using a structure in which a plurality of registers connected in series for dividing the body voltage Ebody and a switch for connecting one of the connection nodes and the anode 40 are included. In this case, one of the node is connected to the anode 40 by the switch according to the operation mode of the traveling wave tube 2.

[0041] For example, the magnetic field application power supply 65 has a structure in which a plurality of power supply circuits, each of which generates the coil voltage Es for each operation mode, are included and the coil voltage Es supplied to the magnetic field application device 70 is changed by a switch according to the operation mode of the traveling wave tube 2. Fig. 2 shows an example of a structure in which two power supply circuits connected in series are included and the electric power is supplied to the magnetic field application device 70 from one of two power supply circuits or two power supply circuits according to the operation mode. As the power supply circuit for generating the coil voltage Es, the well-known DC-DC converter may be used like the heater power supply 63. As described later, when the magnetic field for canceling the magnetic flux that leaks from a periodic magnetic field generation device 80 to the cathode 11 is generated by the magnetic field application device 70, the magnetic field application power supply 65 may be integrated with the heater power supply 63. When the magnetic field application power supply 65 is integrated with the heater power supply 63, the strength of the magnetic field generated by the magnetic field application device 70 can be simultaneously changed when the heater voltage Ef is changed according to the operation mode.

[0042] The switch provided in the heater power supply 63, the anode power supply 64, and the magnetic field application power supply 65 may be operated by a switch for operation mode switching provided in the chassis of the power supply device 60 or a control signal transmitted from a control device (not shown) or the like.

[0043] The helix power supply 61 and the collector power supply 62 generate only the required direct-current high voltage. Therefore, for example, the well-known DC-DC converter including an inverter, a transformer, a rectifier circuit, a capacitor for rectification, and the like may be used for these power supplies. In this case, the inverter and the transformer included in the helix power supply 61, the collector power supply 62, the heater power supply 63, the anode power supply 64, and the magnetic field application power supply 65 can be shared.

[0044] Further, the power supply device 60 may include a wehnelt power supply (not shown) which supplies a positive or negative direct-current voltage (wehnelt voltage Ew) determined by using the electric potential H/K of the cathode 11 as a reference to a wehnelt 13. The wehnelt power supply may have a structure in which the direct-current voltage supplied to the wehnelt 13 is changed by the switch according to the operation mode of the traveling wave tube 2 like the anode power supply 64 described above.

[0045] In this example, the traveling wave tube 2 shown in Fig. 1 operates in the multi-mode in which the output power of the RF signal is changed by using the anode voltage Ea or the wehnelt voltage Ew. Further, in this example, heater temperature is changed by changing the heater voltage Ef according to the operation mode of the traveling wave tube 2. Specifically, the heater voltage Ef (the first heater voltage) is set to a high voltage so as to set the heater temperature to a temperature at which the maximum RF output power can be obtained when the traveling wave tube 2 operates in the high power mode. Further, when the traveling wave tube 2 operates in the low power mode, the heater voltage Ef (the second heater voltage) is set to a low voltage so as to set the heater temperature to a temperature at which the required RF output power can be obtained. The operation mode is not limited to two modes: the high power mode and the low power mode. A medium power mode in which the medium RF output power between the maximum RF output power and the required RF output power is outputted may be used.

[0046] Thus, when the heater temperature is decreased by decreasing the heater voltage Ef at the time of the low power mode, the amount of evaporation of the emitter material from the cathode 11 at the time of the low power mode can be suppressed. Further, when the amount of evaporation of the emitter material is suppressed, the amount of evaporation of barium (Ba) itself that is a metal is also suppressed. Accordingly, a withstanding voltage characteristic of the traveling wave tube 2 does not rapidly deteriorate. Therefore, the product life of the traveling wave tube 2 can be extended according to a period of time when the traveling wave tube 2 is operated in the low power mode.

[0047] Further, in the example, the change in the diameter of the electron beam 50 is suppressed by generating the magnetic field in the neighborhood of the cathode 11 by using the magnetic field application device 70 shown in Fig. 1 and changing the strength of the magnetic field according to the operation mode of the traveling wave tube 2. As a result, the gain change and the amplification efficiency change of the traveling wave tube that occurs when the operation mode is changed can be suppressed.

[0048] Because the strength of the magnetic field generated by the magnetic field application device 70 depends on a value of the current flowing through the coil, the strength of the magnetic field generated by the magnetic field application device 70 is changed by changing the coil voltage Es supplied from the magnetic field application power supply 65 according to the operation mode of the traveling wave tube 2.

[0049] The diameter of the electron beam 50 can be controlled by the magnetic field generated by the magnetic field application device 70. The reason of this will be explained below by using Fig. 4(a) and Fig. 4(b).

[0050] Fig. 4(a) is a schematic diagram showing a state of a magnetic field generated by the magnetic field application device and the periodic magnetic field generation device, and Fig. 4(b) is an enlarged schematic diagram showing a main part of Fig. 4(a).

[0051] As shown in Fig. 4(a) and Fig. 4(b), the periodic magnetic field generation device 80 provided in the traveling wave tube 2 has a structure in which a plurality of ring-shaped pole pieces 81, a plurality of ring-shaped permanent magnets 82, and a plurality of spacers 83 are included. A plurality of the ring-shaped pole pieces 81 are made of a magnetic substance. Each of a plurality of the ring-shaped permanent magnets 82 is arranged between the pole pieces 81 so that the magnetic dipole with a reverse polarity is alternately arranged. The plurality of spacers 83 support a plurality of the permanent magnets 82 mentioned above. Although not shown in Fig. 4(a) and Fig. 4(b), the helix 20 is arranged in an opening of the periodic magnetic field generation device 80 that is formed in a ring shape.

[0052] In such structure, the magnetic field whose magnetic line of force is alternately reversed according to the travel distance of the electron, as shown as a center magnetic field pattern in Fig. 4(a) and Fig. 4(b), is generated in the opening of the periodic magnetic field generation device 80.

[0053] In the traveling wave tube 2, each electron emitted from the cathode 11 travels toward the center by a shape (a spherical surface shape) of the electron emitting surface of the cathode 11 and the electric field generated by the wehnelt 13 and the electrons are converged on a center. The electron that reaches the opening of the periodic magnetic field generation device 80 travels while spirally rotating by the force (Lorentz force) received from the magnetic field generated by the periodic magnetic field generation device 80 and whereby, diffusion of the electrons can be suppressed.

[0054] On the other hand, the magnetic flux of the magnetic field (the main magnetic field) generated by the periodic magnetic field generation device 80 leaks to the neighborhood of the cathode 11 and as shown as a center magnetic field pattern in Fig. 4(a) and Fig. 4(b), the magnetic field with a magnetic flux density Bc is generated in the neighborhood of the electron emitting surface of the cathode 11. When the magnetic field is generated in the neighborhood of the electron emitting surface of the cathode 11, the electron emitted from the cathode 11 receives the force toward outside according to Fleming's left hand rule. Namely, the magnetic field generated in the neighborhood of the electron emitting surface of the cathode 11 by the leakage flux acts so as to expand the electron beam 50. Accordingly, by generating the magnetic field for cancelling the leakage flux by the magnetic field application device 70 and adjusting the strength of the leakage flux, the diameter of the electron beam 50 can be controlled.

[0055] Further, in the neighborhood of the electron emitting surface of the cathode 11, the direction in which the electron beam is emitted has axial and radial components and a direction of the radial component is a direction toward the inside because of the structure of the electrode. Because the electron has a negative charge, an electric current direction is opposite to a direction in which the electrons move and is a direction toward the outside. Therefore, "the current flow direction" given by Fleming's left hand rule is the radial direction toward the outside. The magnetic field in "the direction of the magnetic field" given by Fleming's left hand rule is induced by the leakage flux of the periodic magnetic field generation device 80. Therefore, the main component of the magnetic field is the magnetic field in the axial direction. "The force acting on the conductor" is a force acting on the electron and is a force in the direction of the tangent to the circle according to Fleming's left hand rule. Namely, because the electron moves toward the inside and receives the force in the direction of the tangent, the electron moves toward the outside in comparison with an original state in which no magnetic field exists. When the strength of the magnetic field on the cathode electron emitting surface is large, the tangential direction component of the traveling direction of the electron is large. Therefore, the force toward the outside becomes large.

[0056] A common traveling wave tube is designed so that the magnetic flux leaked in the neighborhood of cathode 11 from the periodic magnetic field generation device 80 is as small as possible in order to suppress the expansion of the electron beam 50 by the leakage flux of the periodic magnetic field generation device 80. In contrast, the traveling wave tube 2 according to the present example can be designed so that in the neighborhood of cathode 11, the leakage flux of the periodic magnetic field generation device 80 is greater than that of the common traveling wave tube. In order to get the large leakage flux in the neighborhood of cathode 11, for example, the diameter of the opening of the anode 40 through which the electron passes may be increased when the anode 40 is made of the magnetic substance. Further, as a method for getting a large leakage flux in the neighborhood of cathode 11, a method in which the periodic magnetic field generation device 80 is expanded in a direction toward the cathode 11 (the electron gun) or a method in which the whole periodic magnetic field generation device 80 is disposed near the cathode 11 (the electron gun) may be used.

[0057] As shown in Fig. 4(a) and Fig. 4(b), in general, the direction of the magnetic line of force of the leakage flux is a direction from the periodic magnetic field generation device 80 toward the cathode 11 (a direction toward the left side of the Figures). Accordingly, the magnetic field of which the direction of the magnetic line of force is a direction from the cathode 11 toward the periodic magnetic field generation device 80 (a direction toward the right side of Figures) is generated by the magnetic field application device 70. For example, the coil is formed by winding a wiring material clockwise around the seal plate 21 to the traveling direction of the electron and when the current flows clockwise through the coil, the magnetic line of force toward the right side of Figures is generated according to the well-known right-handed screw rule. When the electron beam 50 having a large diameter is required, the magnetic field generated by the magnetic field application device 70 is weakened (the low coil voltage Es is supplied) and whereby, the magnetic field of the leakage flux is strengthened. In contrast, when the electron beam 50 having a small diameter is required, the magnetic field generated by the magnetic field application device 70 is strengthened (the high coil voltage Es is supplied) and whereby, the magnetic field of the leakage flux is weakened.

[0058] As described above and in accordance with the present invention, in a case in which the traveling wave tube 2 is designed so that the optimal trajectory of the electron beam 50 can be obtained when the traveling wave tube 2 operates in the high power mode, when the traveling wave tube 2 operates in the low power mode, the amount of electrons emitted from the cathode 11 is decreased and the diameter of the electron beam 50 is decreased in comparison with a case in which the traveling wave tube 2 operates in the high power mode. In this case, the diameter of the electron beam 50 is increased by the diameter approximately equal to the diameter obtained when the traveling wave tube 2 operates in the high power mode by weakening the magnetic field generated by the magnetic field application device 70 by supplying the electric power smaller than the electric power supplied at the time of the high power mode. When the diameter of the electron beam 50 is approximately equal to the diameter obtained when the traveling wave tube 2 operates in the high power mode, the strength of the interaction between the electron beam 50 and the RF signal inputted to the helix 20 becomes approximately equal to the strength obtained when the traveling wave tube 2 operates in the high power mode. Therefore, the reduction of the gain of the traveling wave tube 2 operating in the low power mode can be suppressed. Further, when the diameter of the electron beam 50 is approximately equal to the diameter obtained when the traveling wave tube 2 operates in the high power mode, an amount of ripple of the electron beam 50 is decreased and whereby, the reduction of the amplification efficiency of the traveling wave tube 2 is also suppressed.

[0059] On the other hand, and also in accordance with the present invention, in a case in which the traveling wave tube 2 is designed so that the optimal trajectory of the electron beam 50 can be obtained when the traveling wave tube 2 operates in the low power mode, when the traveling wave tube 2 operates in the high power mode, the amount of electrons emitted from the cathode 11 is increased and the diameter of the electron beam 50 is increased in comparison with a case in which the traveling wave tube 2 operates in the low power mode. In this case, the diameter of the electron beam 50 is decreased by the diameter approximately equal to the diameter obtained when the traveling wave tube 2 operates in the low power mode by strengthening the magnetic field generated by the magnetic field application device 70 by supplying the electric power greater than the electric power supplied at the time of the low power mode. When the diameter of the electron beam 50 is approximately equal to the diameter obtained when the traveling wave tube 2 operates in the low power mode, the strength of the interaction between the electron beam 50 and the RF signal inputted to the helix 20 becomes approximately equal to the strength obtained when the traveling wave tube 2 operates in the low power mode. Therefore, the increase of the gain of the traveling wave tube 2 can be suppressed and whereby, a possibility that the traveling wave tube 2 oscillates is reduced.

[0060] Further, in the above-mentioned description, an example in which the electric power of the RF signal outputted from the traveling wave tube 2 is changed by the anode voltage Ea has been explained by using Fig. 1, Fig. 2, Fig. 4(a), and Fig. 4(b). However, as mentioned above, the electric power of the RF signal outputted from the traveling wave tube 2 can also be controlled by the wehnelt voltage Ew. Fig. 5(a) and Fig. 5(b) show an example of a structure in which the output power of the RF signal is changed by the wehnelt voltage Ew as shown above.

[0061] Fig. 5(a) is a schematic diagram showing operation at the time of the high power mode of a modification example of the high-frequency circuit system according to the present invention, and Fig. 5(b) is a schematic diagram showing operation at the time of the low power mode of a modification example of the high-frequency circuit system according to the present invention. Further, Fig. 5(a) and Fig. 5(b) show an example of a structure in which the electric power is supplied from the heater power supply 63 to the magnetic field application device 70 like the structure shown in Fig. 1.

[0062] As shown in Fig. 5(a) and Fig. 5(b), when the electric power of the RF signal outputted from the traveling wave tube 2 is controlled by the wehnelt voltage Ew, the negative direct-current voltage (wehnelt voltage Ew) determined by using, for example the electric potential H/K of the cathode 11 as a reference is supplied to the wehnelt 13.

[0063] When the traveling wave tube 2 is operated in the high power mode, as shown in Fig. 5(a), the negative direct-current voltage (first wehnelt voltage Ew: Low) having a small difference with the cathode potential H/K is supplied to the wehnelt 13. Further, at the time of the high power mode, the electric potential of the wehnelt 13 may be equal to the electric potential H/K of the cathode 11 and the positive direct-current voltage determined by using the electric potential H/K of the cathode 11 as a reference may be supplied to the wehnelt 13.

[0064] On the other hand, as shown in Fig. 5(b), when the traveling wave tube 2 is operated in the low power mode, the negative direct-current high voltage (second wehnelt voltage Ew: High) higher than the direct-current voltage supplied at the time of the high power mode is supplied to the wehnelt 13.

[0065] The operation for changing the heater temperature and the operation for changing the magnetic field generated by the magnetic field application device 70 are similar to the above-mentioned operation for changing the output power of the RF signal by the anode voltage Ea. Therefore, the description will be omitted.

[0066] Further, in the above-mentioned description, an example in which the magnetic field application device 70 generates the magnetic field for canceling the leakage flux of the periodic magnetic field generation device 80 has been described. However, the magnetic field application device 70 may generate the magnetic field for strengthening the leakage flux of the periodic magnetic field generation device 80. Namely, in Fig. 4(a) and Fig. 4(b), the magnetic field application device 70 may generate the magnetic field of which the direction of the magnetic line of force is the direction from the periodic magnetic field generation device 80 toward the cathode 11 (the direction toward the left side of Figures). In this case, the traveling wave tube 2 according to the present invention may be designed so that the leakage flux of the periodic magnetic field generation device 80 in the neighborhood of cathode 11 is decreased like the common traveling wave tube.

[0067] In the case in which the traveling wave tube 2 is designed so that the optimal trajectory of the electron beam 50 can be obtained when the traveling wave tube 2 operates in the high power mode, the magnetic field generated by the magnetic field application device 70 is strengthened by supplying an electric power greater than the electric power supplied at the time of the high power mode to the magnetic field application device 70 when the traveling wave tube operates in the low power mode. Thus, at the time of the low power mode, the diameter of the electron beam 50 may be increased by the diameter approximately equal to the diameter obtained when the traveling wave tube 2 is operated in the high power mode.

[0068] Further, in the case in which the traveling wave tube 2 is designed so that the optimal trajectory of the electron beam 50 can be obtained when the traveling wave tube 2 operates in the low power mode, the magnetic field generated by the magnetic field application device 70 is weakened by supplying an electric power smaller than the electric power supplied at the time of the low power mode to the magnetic field application device 70 when the traveling wave tube 2 operates in the high power mode. Thus, at the time of the high power mode, the diameter of the electron beam 50 may be decreased by the diameter approximately equal to the diameter obtained when the traveling wave tube 2 is operated in the low power mode. In such structure, the magnetic field application power supply 65 cannot be integrated with the heater power supply 63. However, by using the above-mentioned method, the diameter of the electron beam 50 can be controlled by the magnetic field generated by the magnetic field application device 70.

[0069] In the present invention, a structure in which the heater temperature is changed according to the operation mode may be used. Therefore, when the heater temperature at the time of the low power mode is decreased, the amount of evaporation of the emitter material from the cathode 11 at the time of the low power mode can be suppressed. Further, when the amount of evaporation of the emitter material is suppressed, the amount of evaporation of barium (Ba) itself that is a metal is also suppressed and whereby, a withstanding voltage characteristic of the traveling wave tube 2 does not rapidly deteriorate. Therefore, the product life of the traveling wave tube 2 can be extended according to a period of time when the traveling wave tube 2 is operated in the low power mode.

[0070] Further, the magnetic field application device 70 is disposed in the traveling wave tube 2, the strength of the magnetic field generated in the neighborhood of the cathode by the magnetic field application device 70 is changed according to the operation mode, and whereby, the change of the diameter of the electron beam 50 caused by the change of the operation mode can be suppressed. Accordingly, the product life of the traveling wave tube 2 can be extended and the gain change and the amplification efficiency change of the traveling wave tube 2 that occur when the operation mode is changed can be suppressed.

[0071] The present invention has been described above. However, the present invention is not limited to the arrangements mentioned above. Namely, various changes in the configuration or details of the invention of the present application that can be understood by those skilled in the art can be made without departing from the scope of the invention of the present application.

[0072] This application is based upon and claims the benefit of priority from Japanese patent application No. 2014-133645, filed on June 30, 2014.

[Reference Signs List]

[0073] 

1, 2

traveling wave tube

10

electron gun

11

cathode

12

heater

13

wehnelt

20

helix

30

collector

40

anode

50

electron beam

60

power supply device

61

helix power supply

62

collector power supply

63

heater power supply

64

anode power supply

65

magnetic field application power supply

70

magnetic field application device

80

periodic magnetic field generation device

81

pole piece

82

permanent magnet

83

spacer

Claims

1. A high-frequency circuit system with a traveling wave tube (1, 2), the traveling wave tube (1, 2) comprising:

an electron gun (10) including a cathode (11) for emitting electrons and a heater (12) for giving heat energy for emitting electrons from the cathode (11),

a helix (20) in which an electron beam formed of said electrons emitted from the electron gun (10) interacts with an RF, Radio Frequency, signal,

a periodic magnetic field generation device (80) for generating a magnetic field for suppressing the expansion of the electron beam passing through the helix (20),

a collector (30) for capturing the electron beam output from the helix (20),

an anode (40) for guiding the electrons emitted from the electron gun (10) into the helix (20), and

a magnetic field application device (70) arrange for changing a magnetic field for changing the diameter of the electron beam, characterized in that the traveling wave tube is arranged to be operated at high power mode, at which the output power of the RF signal is maximum, or at a low power mode, at which the output power of the RF signal is low compared with the output power of the RF signal in the high power mode,

and in that the high-frequency circuit system further comprises a magnetic field application power supply (65) arranged for supplying electric power to the magnetic field application device (70) for generating the magnetic field, the magnetic field application power supply being configured to supply at the time of a low power mode an electric power to the magnetic field application device (70) that is smaller than the electric power supplied at the time of high power mode, in a case in which the traveling wave tube (1, 2) is designed so that the optimal trajectory of the electron beam can be obtained when the traveling wave tube (1, 2) operates in the high power mode, and to supply at the time of the high power mode an electric power to the magnetic field application device (70) that is greater than the electric power supplied at the time of a low power mode, in a case

in which the traveling wave tube (1, 2) is designed so that the optimal trajectory of the electron beam can be obtained when the traveling wave tube (1, 2) operates in the low power mode.

2. The system according to claim 1, wherein
the magnetic field application device (70) generates the magnetic field including a magnetic line of force whose direction is approximately orthogonal to the electron emitting surface of the cathode (1 1).

3. The system according to claim 1 or 2, wherein
the magnetic field application device (70) is a coil formed on a seal plate for sealing a chassis from a rear direction of the electron gun (10) that faces the electron emitting surface.

4. The system according to claim 3, wherein
the seal plate is made of a magnetic substance material.

5. The system according to claim 1 or 2, wherein
the magnetic field application device (70) comprises:

a seal plate and a magnetic substance core that is disposed in periphery of the seal plate for sealing the chassis from the rear direction of the electron gun (10) that faces the electron emitting surface and made of the magnetic substance material and

a coil formed on the periphery of the magnetic substance core.

6. A system according to any one of claims 1 to 5, further comprising a power supply device (60) for supplying a required direct-current voltage to the traveling wave tube (1, 2); wherein
the power supply device (60) comprises:

an anode power supply which can supply one of two or more anode voltages to the anode (40) by changing the anode voltage according to an instruction from an outside,

a heater power supply (63) which can supply one of two or more heater voltages to the heater (12) by changing the heater voltage according to an instruction from an outside, and

the magnetic field application power supply (65) which can supply one of two or more electric powers to the magnetic field application device (70) by changing the electric power according to an instruction from an outside.

7. The system described in claim 6, wherein
the anode power supply supplies a first anode voltage to the anode (40) when in the high power mode of the traveling wave tube (1, 2), and supplies a second anode voltage lower than the first anode voltage to the anode (40) when in a low power mode;
the heater power supply (63) supplies a first heater voltage to the heater (12) in the high power mode, and supplies a second heater voltage lower than the first heater voltage to the heater (12) in the low power mode.

8. A system according to any one of claims 1 to 5, further comprising a power supply device for supplying a required direct-current voltage to the traveling wave tube (1, 2), wherein
the electron gun (10) is equipped with a wehnelt for focusing the electrons emitted from the cathode (11) and
the power supply device includes:

a wehnelt power supply which can supply one of two or more wehnelt voltages to the wehnelt by changing the wehnelt voltage according to an instruction from an outside,

a heater power supply (63) which can supply one of two or more heater voltages to the heater (12) by changing the heater voltage according to an instruction from an outside, and

the magnetic field application power supply (65) which can supply one of two or more electric powers to the magnetic field application device (70) by changing the electric power according to an instruction from an outside.

9. The system according to claim 8, wherein
the wehnelt power supply is arranged to supply a first wehnelt voltage that is a negative voltage to the wehnelt at the time of the high power mode of the traveling wave tube (1, 2), and to supply a second wehnelt voltage that is a negative voltage higher than the first wehnelt voltage to the wehnelt at the time of the low power mode of the traveling wave tube (1, 2);
the heater power supply (63) is arranged to supply a first heater voltage to the heater (12) at the time of the high power mode, and to supply a second heater voltage lower than the first heater voltage to the heater (12) at the time of the low power mode.

10. The system according to any one of claims 6 to 9, wherein
the magnetic field application power supply (65) is integrated with the heater power supply (63), for generating a magnetic field by the magnetic field application device for cancelling a magnetic flux leaked from the periodic magnetic field generation device to the cathode.

Ansprüche

1. Hochfrequenzschaltungssystem mit einer Wanderfeldröhre (1, 2), wobei die Wanderfeldröhre (1, 2) aufweist:

eine Elektronenkanone (10) mit einer Kathode (11) zum Emittieren von Elektronen und einer Heizeinrichtung (12) zum Abgeben von Wärmeenergie zum Emittieren von Elektronen von der Kathode (11);

eine Helix (20), in der ein Elektronenstrahl, der aus den von der Elektronenkanone (10) emittierten Elektronen gebildet wird, mit einem HF-, Hochfrequenz, Signal wechselwirkt;

eine Vorrichtung (80) zum Erzeugen eines periodischen Magnetfelds zum Erzeugen eines Magnetfelds zum Unterdrücken der Ausdehnung des die Helix (20) durchlaufenden Elektronenstrahls;

einen Kollektor (30) zum Auffangen des von der Helix (20) ausgegebenen Elektronenstrahls;

eine Anode (40) zum Führen der von der Elektronenkanone emittierten Elektronen (10) in die Helix (20); und

eine Magnetfeldanwendungseinrichtung (70), die dazu eingerichtet ist, ein Magnetfeld zu ändern, um den Durchmesser des Elektronenstrahls zu ändern,

dadurch gekennzeichnet, dass

die Wanderfeldröhre dazu eingerichtet ist, in einem Hochleistungsmodus betrieben zu werden, in dem die Ausgangsleistung des HF-Signals maximal ist, oder in einem Niedrigleistungsmodus, in dem die Ausgangsleistung des HF-Signals im Vergleich zur Ausgangsleistung des HF-Signals im Hochleistungsmodus niedrig ist; und

dadurch, dass das Hochfrequenzschaltungssystem ferner eine Magnetfeldanwendungseinrichtungsstromversorgung (65) aufweist, die dazu eingerichtet ist, der Magnetfeldanwendungseinrichtung (70) elektrischen Strom zum Erzeugen des Magnetfelds zuzuführen,

wobei die Magnetfeldanwendungseinrichtungsstromversorgung dafür konfiguriert ist, um während eines Niedrigleistungsmodus der Magnetfeldanwendungseinrichtung (70) eine elektrische Leistung zuzuführen, die niedriger ist als die während des Hochleistungsmodus zugeführte elektrische Leistung,

in einem Fall, in dem die Wanderfeldröhre (1, 2) derart eingerichtet ist, dass die optimale Trajektorie des Elektronenstrahls erhalten werden kann, wenn die Wanderfeldröhre (1, 2) im Hochleistungsmodus betrieben wird, und

während des Hochleistungsmodus der Magnetfeldanwendungseinrichtung (70) eine elektrische Leistung zuzuführen, die größer ist als die während eines Niedrigleistungsmodus zugeführte elektrische Leistung,

in einem Fall, in dem die Wanderfeldröhre (1, 2) derart eingerichtet ist, dass die optimale Trajektorie des Elektronenstrahls erhalten werden kann, wenn die Wanderfeldröhre (1, 2) im Niedrigleistungsmodus betrieben wird.

2. System nach Anspruch 1, wobei
die Magnetfeldanwendungseinrichtung (70) das Magnetfeld mit einer magnetischen Kraftlinie erzeugt, deren Richtung sich ungefähr orthogonal zur elektronenemittierenden Oberfläche der Kathode (11) erstreckt.

3. System nach Anspruch 1 oder 2, wobei
die Magnetfeldanwendungseinrichtung (70) eine Spule ist, die auf einer Dichtungsplatte zum Abdichten eines Rahmens von einer hinteren Richtung der Elektronenkanone (10) ausgebildet ist, die der elektronenemittierenden Oberfläche zugewandt ist.

4. System nach Anspruch 3, wobei
die Dichtungsplatte aus einem magnetischen Substanzmaterial besteht.

5. System nach Anspruch 1 oder 2, wobei die Magnetfeldanwendungseinrichtung (70) aufweist:

eine Dichtungsplatte und einen Kern aus einer magnetischen Substanz, der am Umfang der Dichtungsplatte zum Abdichten des Rahmens aus der hinteren Richtung der Elektronenkanone (10) angeordnet ist, die der elektronenemittierenden Oberfläche zugewandt ist, und aus dem magnetischen Substanzmaterial besteht; und

eine am Umfang des Kerns aus der magnetischen Substanz ausgebildete Spule.

6. System nach einem der Ansprüche 1 bis 5, ferner mit einer Stromversorgungseinrichtung (60) zum Zuführen einer erforderlichen Gleichspannung zur Wanderfeldröhre (1, 2),
wobei die Stromversorgungseinrichtung (60) aufweist:

eine Anodenstromversorgung, die der Anode (40) durch Ändern der Anodenspannung gemäß einer Anweisung von außen eine von zwei oder mehr Anodenspannungen zuführen kann;

eine Heizeinrichtungsstromversorgung (63), die der Heizeinrichtung (12) durch Ändern der Heizeinrichtungsspannung gemäß einer Anweisung von außen eine von zwei oder mehr Heizeinrichtungsspannungen zuführen kann; und

die Magnetfeldanwendungseinrichtungsstromversorgung (65), die der Magnetfeldanwendungseinrichtung (70) durch Ändern der elektrischen Leistung gemäß einer Anweisung von außen eine von zwei oder mehr elektrischen Leistungen zuführen kann.

7. System nach Anspruch 6, wobei

die Anodenstromversorgung der Anode (40) im Hochleistungsmodus der Wanderfeldröhre (1, 2) eine erste Anodenspannung zuführt und der Anode (40) im Niedrigleistungsmodus eine zweite Anodenspannung zuführt, die niedriger ist als die erste Anodenspannung, und

die Heizeinrichtungsstromversorgung (63) der Heizeinrichtung (12) im Hochleistungsmodus eine erste Heizeinrichtungsspannung zuführt und der Heizeinrichtung (12) im Niedrigleistungsmodus eine zweite Heizeinrichtungsspannung zuführt, die niedriger ist als die erste Heizeinrichtungsspannung.

8. System nach einem der Ansprüche 1 bis 5, ferner mit einer Stromversorgungseinrichtung zum Zuführen einer erforderlichen Gleichspannung zur Wanderfeldröhre (1, 2), wobei die Elektronenkanone (10) einen Wehneltzylinder zum Fokussieren der von der Kathode (11) emittierten Elektronen aufweist, und
die Stromversorgungseinrichtung aufweist:

eine Wehneltzylinder-Stromversorgung, die dem Wehneltzylinder durch Ändern der Wehneltzylinder-Spannung gemäß einer Anweisung von außen eine von zwei oder mehr Wehneltzylinder-Spannungen zuführen kann;

eine Heizeinrichtungsstromversorgung (63), die der Heizeinrichtung (12) durch Ändern der Heizeinrichtungsspannung gemäß einer Anweisung von außen eine von zwei oder mehr Heizeinrichtungsspannungen zuführen kann; und

die Magnetfeldanwendungseinrichtungsstromversorgung (65), die der Magnetfeldanwendungseinrichtung (70) durch Ändern der elektrischen Leistung gemäß einer Anweisung von außen eine von zwei oder mehr elektrischen Leistungen zuführen kann.

9. System nach Anspruch 8, wobei

die Wehneltzylinder-Stromversorgung dafür eingerichtet ist, dem Wehneltzylinder während des Hochleistungsmodus der Wanderfeldröhre (1, 2) eine erste Wehneltzylinder-Spannung zuzuführen, die eine negative Spannung ist, und

dem Wehneltzylinder während des Niedrigleistungsmodus der Wanderfeldröhre (1, 2) eine zweite Wehneltzylinder-Spannung zuzuführen, die eine negative Spannung ist, die höher ist als die erste Wehneltzylinder-Spannung;

wobei die Heizeinrichtungsstromversorgung (63) derart eingerichtet ist, dass sie der Heizeinrichtung (12) während des Hochleistungsmodus eine erste Heizeinrichtungsspannung zuführt, und der Heizeinrichtung (12) während des Niedrigleistungsmodus eine zweite Heizeinrichtungsspannung zuführt, die niedriger ist als die erste Heizeinrichtungsspannung.

10. System nach einem der Ansprüche 6 bis 9, wobei
die Magnetfeldanwendungseinrichtungsstromversorgung (65) in der Heizeinrichtungsstromversorgung (63) integriert ist, um durch die Magnetfeldanwendungseinrichtung ein Magnetfeld zum Kompensieren eines Magnetflusses zu erzeugen, der von der Einrichtung zum Erzeugen eines periodischen Magnetfelds zur Kathode ausgetreten ist.

Revendications

1. Système de circuit haute fréquence avec un tube à ondes progressives (1, 2), le tube à ondes progressives (1, 2) comprenant :

un canon à électrons (10) incluant une cathode (11) pour émettre des électrons, et un dispositif de chauffage (12) pour fournir de l'énergie thermique afin d'émettre des électrons à partir de la cathode (11) ;

une hélice (20) dans laquelle un faisceau d'électrons formé desdits électrons émis à partir du canon à électrons (10) interagit avec un signal radiofréquence, RF ;

un dispositif de génération de champ magnétique périodique (80) destiné à générer un champ magnétique afin de supprimer l'expansion du faisceau d'électrons traversant l'hélice (20) ;

un collecteur (30) destiné à capturer le faisceau d'électrons émis à partir de l'hélice (20) ;

une anode (40) destinée à guider les électrons, émis à partir du canon à électrons (10), dans l'hélice (20) ; et

un dispositif d'application de champ magnétique (70) agencé de manière à modifier un champ magnétique afin de modifier le diamètre du faisceau d'électrons, caractérisé en ce que le tube à ondes progressives est agencé de manière à fonctionner en mode haute puissance, dans lequel la puissance de sortie du signal RF est maximale, ou en mode basse puissance, dans lequel la puissance de sortie du signal RF est faible par rapport à la puissance de sortie du signal RF en mode haute puissance, et en ce que le système de circuit haute fréquence comprend en outre une alimentation électrique d'application de champ magnétique (65), agencée de manière à fournir une puissance électrique au dispositif d'application de champ magnétique (70) en vue de générer le champ magnétique, l'alimentation électrique d'application de champ magnétique étant configurée de manière à fournir, au moment où le mode basse puissance est en cours d'utilisation, une puissance électrique, au dispositif d'application de champ magnétique (70), laquelle est inférieure à la puissance électrique fournie à un moment où le mode haute puissance est en cours d'utilisation, dans un cas où le tube à ondes progressives (1, 2) est conçu de sorte que la trajectoire optimale du faisceau d'électrons peut être obtenue lorsque le tube à ondes progressives (1, 2) opère en mode haute puissance, et à fournir, au moment où le mode haute puissance est en cours d'utilisation, une puissance électrique, au dispositif d'application de champ magnétique (70), laquelle est supérieure à la puissance électrique fournie au moment où le mode basse puissance est en cours d'utilisation, dans un cas où le tube à ondes progressives (1, 2) est conçu de sorte que la trajectoire optimale du faisceau d'électrons peut être obtenue lorsque le tube à ondes progressives (1, 2) opère en mode basse puissance.

2. Système selon la revendication 1, dans lequel :
le dispositif d'application de champ magnétique (70) génère le champ magnétique incluant une ligne de force magnétique dont la direction est approximativement orthogonale à la surface émettrice d'électrons de la cathode (11).

3. Système selon la revendication 1 ou 2, dans lequel :
le dispositif d'application de champ magnétique (70) est une bobine formée sur une plaque d'étanchéité pour sceller un châssis à partir d'une direction arrière du canon à électrons (10) qui fait face à la surface émettrice d'électrons.

4. Système selon la revendication 3, dans lequel :
la plaque d'étanchéité est constituée d'un matériau de substance magnétique.

5. Système selon la revendication 1 ou 2, dans lequel :
le dispositif d'application de champ magnétique (70) comprend :

une plaque d'étanchéité, et un noyau de substance magnétique qui est disposé à la périphérie de la plaque d'étanchéité pour sceller le châssis à partir de la direction arrière du canon à électrons (10) qui fait face à la surface émettrice d'électrons, et qui est constitué du matériau de substance magnétique ; et

une bobine formée sur la périphérie du noyau de substance magnétique.

6. Système selon l'une quelconque des revendications 1 à 5, comprenant en outre :

un dispositif d'alimentation électrique (60) destiné à fournir une tension continue requise au tube à ondes progressives (1, 2) ; dans lequel

le dispositif d'alimentation électrique (60) comprend :

une alimentation électrique d'anode qui est en mesure de fournir, à l'anode (40), une tension parmi au moins deux tensions anodiques, en modifiant la tension anodique selon une instruction provenant de l'extérieur ;

une alimentation électrique de dispositif de chauffage (63) qui est en mesure de fournir, au dispositif de chauffage (12), une tension parmi au moins deux tensions de dispositif de chauffage, en modifiant la tension de dispositif de chauffage selon une instruction provenant de l'extérieur ; et

l'alimentation électrique d'application de champ magnétique (65) qui est en mesure de fournir, au dispositif d'application de champ magnétique (70), une puissance parmi au moins deux puissances électriques, en modifiant la puissance électrique selon une instruction provenant de l'extérieur.

7. Système selon la revendication 6, dans lequel :

l'alimentation électrique d'anode fournit une première tension anodique à l'anode (40), lorsque le mode haute puissance du tube à ondes progressives (1, 2) est en cours d'utilisation, et fournit une seconde tension anodique, inférieure à la première tension anodique, à l'anode (40), lorsque le mode basse puissance est en cours d'utilisation ;

l'alimentation électrique de dispositif de chauffage (63) fournit, au dispositif de chauffage (12), une première tension de dispositif de chauffage en mode haute puissance, et fournit, au dispositif de chauffage (12), une seconde tension de dispositif de chauffage, inférieure à la première tension de dispositif de chauffage, en mode basse puissance.

8. Système selon l'une quelconque des revendications 1 à 5, comprenant en outre un dispositif d'alimentation électrique pour fournir une tension continue requise au tube à ondes progressives (1, 2), dans lequel :

le canon à électrons (10) est équipé d'une électrode wehnelt pour focaliser les électrons émis à partir de la cathode (11) ; et

le dispositif d'alimentation électrique inclut :

une alimentation électrique d'électrode wehnelt qui est en mesure de fournir, à l'électrode wehnelt, une tension parmi au moins deux tensions d'électrode wehnelt, en modifiant la tension d'électrode wehnelt selon une instruction provenant de l'extérieur ;

une alimentation électrique de dispositif de chauffage (63) qui est en mesure de fournir, au dispositif de chauffage (12), une tension parmi au moins deux tensions de dispositif de chauffage, en modifiant la tension de dispositif de chauffage selon une instruction provenant de l'extérieur, et

l'alimentation électrique d'application de champ magnétique (65) qui est en mesure de fournir, au dispositif d'application de champ magnétique (70), une puissance parmi au moins deux puissances électriques, en modifiant la puissance électrique selon une instruction provenant de l'extérieur.

9. Système selon la revendication 8, dans lequel :

l'alimentation électrique d'électrode wehnelt est agencée de manière à fournir, à l'électrode wehnelt, une première tension d'électrode wehnelt qui est une tension négative, au moment où le mode haute puissance du tube à ondes progressives (1, 2) est en cours d'utilisation, et à fournir, à l'électrode wehnelt, une seconde tension d'électrode wehnelt qui est une tension négative supérieure à la première tension d'électrode wehnelt, au moment où le mode basse puissance du tube à ondes progressives (1, 2) est en cours d'utilisation ;

l'alimentation électrique de dispositif de chauffage (63) est agencée de manière à fournir, au dispositif de chauffage (12), une première tension de dispositif de chauffage, au moment où le mode haute puissance est en cours d'utilisation, et à fournir, au dispositif de chauffage (12), une seconde tension de dispositif de chauffage inférieure à la première tension de dispositif de chauffage, au moment où le mode basse puissance est en cours d'utilisation.

10. Système selon l'une quelconque des revendications 6 à 9, dans lequel :
l'alimentation électrique d'application de champ magnétique (65) est intégrée à l'alimentation électrique du dispositif de chauffage (63), en vue de générer un champ magnétique, par le biais du dispositif d'application de champ magnétique, afin d'annuler un flux magnétique fuyant du dispositif de génération de champ magnétique périodique vers la cathode.

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